Vehicular air conditioning apparatus including a detachably installed mix door assembly

ABSTRACT

An air conditioning apparatus for an automotive vehicle includes a heater core and a mix door assembly installed in a case. The mix door assembly is detachably installed in the case through an opening formed at a side wall of the case. The mix door assembly constitutes a housing, a mix door and a slide mechanism. The slide mechanism is arranged to slide the mix door according to a received rotational force so as to vary the ratio of warm air to quantity and cool air quantity.

BACKGROUND OF THE INVENTION

The present invention relates to an air conditioning apparatus employinga slide-type air mix door, and more particularly to an air conditioningapparatus for an automotive vehicle which apparatus employs a slide doorfor controlling a ratio between quantities of warm air and cool air.

Various air conditioning apparatuses have been proposed and in practicaluse in order to improve easiness of installation to a smaller space ofan automotive vehicles. A so-called vertical type unit is one of compacttypes and is arranged such that a cooler unit and a heater unit areintegrally formed. Further, a slide-type air mix door is installedbetween the cooler unit and the heater unit in order to further improvecompactness of the air conditioning apparatus.

SUMMARY OF THE INVENTION

However, this conventional compact air conditioning apparatus has beenproduced by assembling elements for a mix door mechanism into a unitcase one by one during assembling operations of various mode doors.Further, it is necessary to install a driving device for sliding the mixdoor after the mix door mechanism is installed in the unit case. Thisalso increases steps for assembling the air conditioning apparatus.

It is therefore an object of the present invention to provide animproved air conditioning apparatus which employs a slide-type mix doorassembly to largely improve operational easiness during a productionprocess thereof and decreases the production cost of the airconditioning apparatus.

An aspect of the present invention resides in an air conditioningapparatus which is for an automotive and comprises a case, a heater coreinstalled in the case and a mix door assembly. The mix door assembly isdetachably installed in the case through an opening formed at a sidewall of the case. The mix door assembly varies a ratio of a quantity ofair passing through the heater core and a quantity of air bypassing theheater core. The mix door assembly is constituted by a housing, a mixdoor and a slide mechanism. The slide mechanism receives a rotationalforce and slides the mix door according to the received rotational forceto vary the ratio.

Another aspect of the present invention resides in a mix door assemblydetachably installed in a case of an air conditioning apparatus for anautomotive vehicle. The mix door assembly comprises a housing, a doorand a slide mechanism. The housing has an opening which generallycorresponds to a cross section of an air conditioning passage defined inthe case. The door is installed in the housing and partly closes theopening. The door slides in the housing to change a closed portion ofthe opening. The slide mechanism comprises a rack integrally formed on asurface of said door and a pinion rotatably supported to the sideplates. The pinion is engaged with the rack, receives a rotational forceand slides the door according to the received rotational force.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic cross-sectional view showing a first embodiment ofan air conditioning apparatus according to the present invention.

FIGS. 2A and 2B are a plan view and a side view of a mix door assemblyemployed in the air conditioning apparatus of FIG. 1.

FIG. 3 is a perspective view showing a partly-cut mix door of the mixdoor assembly of the first embodiment.

FIG. 4 is a cross-sectional view showing a slide mechanism of the mixdoor assembly of the first embodiment.

FIG. 5 is a cross-sectional view taken in the direction of arrowssubstantially in the direction of the line V—V of FIG. 4.

FIG. 6 is an explanatory view employed for explaining a shape of guidegrooves.

FIG. 7 is a cross-sectional view showing a slide mechanism employed inthe mix door assembly of a second embodiment according to the presentinvention.

FIG. 8 is an exploded perspective view showing the air conditioningapparatus of a third embodiment according to the present invention.

FIG. 9 is an exploded perspective view showing the mix door assembly ofthe air conditioning apparatus of a fourth embodiment according to thepresent invention.

FIG. 10 is a cross-sectional view showing the air conditioning apparatusof a fifth embodiment according to the present invention.

FIG. 11 is a perspective view showing the mix door employed in the fifthembodiment of FIG. 10.

FIG. 12 is a cross-sectional view showing the air conditioning apparatusof a sixth embodiment according to the present invention.

FIG. 13 is a perspective view showing a half part of a unit caseemployed in the sixth embodiment of FIG. 12.

FIG. 14 is a perspective view showing the air conditioning apparatus ofthe sixth embodiment.

FIG. 15 is an exploded perspective view showing the mix door assemblyemployed in the six embodiment.

FIG. 16 is a perspective view showing the mix door assembly employed inthe sixth embodiment.

FIG. 17 is a cross-sectional view showing a supporting structure of themix door assembly of the sixth embodiment.

FIG. 18 is a partial cross-sectional view showing an installationstructure of the mix door assembly to the unit case in the sixthembodiment.

DETAILED DESCRIPTION OF THE INVENTION

Referring to FIGS. 1 to 6, there is shown a first embodiment of an airconditioning apparatus according to the present invention.

The air conditioning apparatus is for an automotive vehicle andcomprises a cooler unit 1 and a heater unit 2 which are arranged in thefore-and-aft direction (longitudinal direction) of the vehicle. Morespecifically, a front end portion of the heater unit 2 is integrallyassembled with a rear end portion of the cooler unit 1 in a case 60 soas to decrease a longitudinal dimension of the air conditioningapparatus. Further, an evaporator 3 of the cooler unit 1 is disposed inan upstream passage in the case 60, and a heater core 4 of the heaterunit 2 is disposed in a downstream passage in the case 60. The case 60is constituted by a pair of case members which are divided along alongitudinal direction of the vehicle. The evaporator 3 includes aconnecting portion 3 a that includes a refrigerant inlet port 3 b and arefrigerant outlet port 3 c. The connecting portion 3 a is arranged tobe connected to a refrigerant line outside of the case 60.

A mix door assembly 10 is disposed between the evaporator 3 and theheater core 4 to control air flow to the heater core 4. Morespecifically, the mix door assembly 10 comprises a mix door 70, a slidemechanism 90 for sliding the mix door 70, and a mix door housing 80 inwhich the mix door 70 and the slide mechanism are installed. There areprovided a warm air passage 82 and a bypass passage 84 at a downstreamside of the mix door assembly 10 in the case 60. The mix door 70 isarranged to slidably move in the housing 80 along the generally verticaldirection. The housing 80 has an opening 34 on which the mix door 70slides while partly closing the mix door 70. Therefore, a ratio of anair quantity to be delivered to the warm air passage 5 and an airquantity to be delivered to the bypass passage 84 is continuouslyvariable according to the position of the mix door 70 with respect tothe opening 34 of the housing 80. Of course, the ratio includes 1:0 and0:1. A mixing zone 9 is provided at a downsteam side of the warm airpassage 82 and the bypass passage 84, and therefore, warm air passedthrough the warm air passage 82 and cool air passed through the bypasspassage 84 are mixed at the mixing zone 9. The mixed air is delivered toa passenger compartment of the vehicle through several outlets 6 a to 8a of the case 60. Mode doors 6 to 8 are installed to the outlets 6 a to8 a, respectively, and the respective opening degrees of the mode doors6 to 8 are controlled by a driver and/or a control unit (not shown) ofthe air conditioning apparatus. Accordingly, a temperature of airdelivered to the passenger compartment through the outlets 6 a to 8 a isdetermined by controlling the vertical position of the mix door 70 withrespect to the opening 34 of the housing 80.

When the mix door assembly 10 is assembled with the case 60, it isinserted through an opening 60 a formed at a side wall of the case 60.That is, the mix door assembly 10 is inserted to the case 60 in theperpendicular direction of a sheet surface of FIG. 1. In order to enablethe mix door assembly 10 to be smoothly inserted to the case 60, thecase 60 has guide members G1 and G2 which are formed along a traversedirection of the case 60. The guide member G1 and G2 support and guideupper and lower portions of the housing 80, respectively.

The mix door 70 of the mix door assembly 10 comprises a door main body12 through which practically and partially closes a part of the opening34 of the mix door assembly 10. As shown in FIG. 1, a vertical dimensionof the mix door main body 12 is generally half the opening 34, and ahorizontal dimension thereof is generally the same as that of the case60.

As shown in FIG. 3, the mix door main body 12 is generally a rectangularcurved plate and is constituted by upper and lower flat portions 12 aand a bulged portion 12 b between the upper and lower flat portions 12a. An outwardly protruding surface of the mix door main body 12 iscovered with a sealing member 15 made of urethane foam through adhesive.

A pair of reinforcement plates (ribs) 16 are installed to lateral sideportions of the mix door main body 12. The reinforcement plates 16function as a reinforcement member of the mix door main body 12 and asan air guide for directing air received thereby to the opening 34. Eachlaterally end portion between the reinforcement plate 16 and a lateralend of the mix door main body 12 is formed in an arc-shapedcross-section. A pair of racks 17 are formed on the both laterally endportion of the arc-shape, as shown in FIG. 3. The rack 17 iscontinuously formed from an upper end to a lower end of the air mix door12 and is engaged with a pinion gear 20 driven by a driving device 23.Six small ribs 72 are formed on the bulged portion 12 b as Gus shown inFIG. 2. Four guide rollers 18 are installed at four corner portions ofthe air mix door 12 and projects in the horizontal direction. The guiderollers 18 are set in guide grooves 19 so as to rotatably move therein.The guide rollers 18 may be arranged so as to be slidable in the guidegroove 19. The arc-shaped surface having the racks 17 is defined as adepressed surface against the air flow direction. This depressed surfacefunctions as a guide when the air flow is guided to heater core 4 or thebypass passage 64.

The slide mechanism 90 for moving the air mix door 70 comprises theguide grooves 19, the pinion gears 20 engaged with the racks 17, a shaft21 for interconnected the pinion gears 20, and a drive gear 22 fixed toan end of the shaft 21.

The driving device 23 is installed to a side wall 32 of the housing 80of the mix door assembly 10 so as to rotate the drive gear 22 through agear (not shown). An electric motor or motor actuator including areduction gear in a casing is employed as the driving device 23 in thisembodiment. The drive device 23 may be installed to a side portion ofthe case 60 instead of the side wall 32 of the housing 80.

The guide grooves 19 are formed such that a radius r of curvature of theguide grooves 19 is generally as same as that of the mix door main body12. The four guide rollers 18 are supported to the respective guidegrooves 19 constituted by four grooves of right upper, right lower, leftupper and left lower guide grooves 19. By this arrangement of guidegrooves 19, the mix door main body 12 is smoothly moved along the guidegrooves 19 without generating rattles even if the mix door 70 receivesair flow. Both end portions 19 a of each guide groove 19 are slightlybent toward the downstream side, as shown in FIG. 6. By this arrangementof the guide groove 19, when the guide roller 18 is positioned the endportion 19 a, the side reached the end portions 19 a is slightly tiltedin the rearward direction. Accordingly, the seal member 15 of the tiltedside is fitted with a partition wall of the housing 80 to improve asealing performance therebetween. That is, the seal member 15 is not incontact with the partition wall 31 when the mix door 70 is notpositioned at an uppermost position or lowermost position. Only when itis necessary to prevent the air passes through a clearance between theseal member 15 and the partition wall 31, they are in contact with eachother. This arrangement of the seal mechanism prevents the sealingperformance from being degraded for a long term and ensures a sealingperformance for a long term. Furthermore, this arrangement decreases thefriction during the slide movement of the mix door 70, and thereforethis decreases a necessary force for moving the mix door 70.

The housing 80 of the mix door assembly 10 is integrally produced by amolding of plastic resin. The housing 80 comprises the partition wall 31along a protruding curve of the mix door 70, side walls 32 and upper andlower walls 33. The partition wall 31 has the opening 34 through whichair passed through the evaporator 3 passes. The size and shape of theopening 34 is designed upon taking account of an air-flow resistance anda rigidity of the housing 80. As mentioned above, the guide grooves 19are formed on the side walls 32. Further, four installation grooves 35are formed, as shown in FIG. 2B, to install the guide rollers 18 of themix door main body 12 to the guide grooves 19, respectively.

As shown in FIG. 5, the pinion gear 20 comprises a pair of high toothportions 20 a and a plurality of normal tooth portions 20 b disposedbetween the high tooth portions 20 a. A height of the high tooth portion20 a is higher than that of the normal tooth portion 20 b. The hightooth portion 20 a moves the mix door 70 in the reward direction whenthe mix door 70 is moved to the uppermost position of the lowermostposition.

On the other hand, the rack 17 formed on the mix door main body 12 alsocomprises high tooth portions 17 a disposed at both end of the rack 17and a plurality of normal tooth portions 17 a disposed between the hightooth portions 17 a. The height of the high tooth portions 17 a ishigher than that of the normal tooth portion 17 b. The high toothportions 17 a are arranged so that the height thereof graduallyincreases toward the endmost tooth portion as shown in FIG. 5. That is,the high tooth portions 17 a changes its position so as to change itsradius with respect to the rotation center O shown in FIG. 6.Accordingly, the high tooth portion 17 a of the rack 17 is firmlyengaged with the high tooth portion 20 a of the pinion 20 and thereforethe mix door main body 12 is smoothly slid along the guide grooves 19.

In the assembly process of the air conditioning apparatus according tothe first embodiment of the present invention, the following steps (1)to (4) are executed.

(1) The mix door assembly 10 has been previously assembled by assemblingthe mix door 70 and the slide mechanism 90 including the pinion gear 20into the housing 80 and installing the driving device 23 to the sidewall of the housing 80.

(2) The evaporator 3 and the heater core 4 are installed to thepredetermined positions in the case 60.

(3) The mix door assembly 10 is inserted into the case 60 from theopening formed at the side wall of the case 60.

(4) After the insertion of the mix door assembly 10 into the case 60,the opening is closed by a cover, and the cover is fixed to the case 60by mean of screws or clips. Of course, it will be understood that thiscovering process may be replaced with a side wall of the housing 80 byforming the side wall so as to be larger than the opening of the case 60and to function as a cover.

With the thus arranged air conditioning apparatus according to thepresent invention, the mix door assembly 10 is detachably installed tothe case 60 through the opening formed at the side wall of the case 60after the evaporator 3 and the heater core 4 are installed to the case60. Therefore, the production process of the air conditioning apparatusfor the vehicle is largely improved as compared with a conventionalapparatus whose mix door parts are assembled to the case, respectively.Consequently, the operational easiness during the production process ofthe air conditioning apparatus is improved and therefore it becomespossible to decrease the production cost of the air conditioningapparatus. Further, the mix door assembly 10 can be adapted to variouscases 60 which have various shapes and various positions of air outletsaccording to various vehicles. Therefore, in this regard, theoperational easiness is improved, and it becomes possible to decreasethe production cost of the air conditioning apparatus.

Furthermore, even if the material of the mix door assembly 10 isdifferent form that of the case 60, they are easily disassembled andclassified by kind of material. This improves the easiness of a recycleof the air conditioning apparatus. Further, the installation method ofthe mix door assembly 10 improves the easiness of the maintenance of themix door assembly 10. Additionally, since the positional accuracy of theguide grooves 19 for guiding the guide rollers 18 are improved bypreviously assembling the mix door 70, the slide mechanism 90 and thehousing 80, it becomes possible to ensure the stability of the slidingperformance of the mix door 70 independently, and therefore theoperational reliability of the air mix door is improved. Further, theinstallation of the drive section 23 to the side wall of the housing 80also improves the operational easiness in the production process of theair conditioning apparatus.

Referring to FIG. 7, there is shown a mix door assembly 10 a of the airconditioning apparatus according to a second embodiment of the presentinvention.

A slide mechanism 90 a of the mix door assembly 10 a is arranged suchthat an output shaft 24 of the driving device 23 a is coaxiallyconnected to the pair of the pinion gears 20. The pinion gears 20 areengaged with the pair of the racks 17 formed on the air mix door 70,respectively. The pinion gears 20 are fixed to the shaft 21 by means ofscrews, and one of the pinion gear 20 fixed to the output shaft 24 bymeans of screws.

A housing opening 25 is formed at a side wall 32 a of the housing 80 a,and the shafts 21 and 24 are inserted to the housing 80 a through thehousing opening 25. The housing opening 25 is covered with a side wallof the driving device 23 a as shown in FIG. 7. The side wall of thediving device 23 a is provided with a ring-shaped engaging projection26. The circular engage projection 26 is sealingly engaged with aring-shaped depression 27 which is formed at a periphery of the hosingopening 25. The other construction of the second embodiment is the sameas that of the first embodiment. Therefore, the same elements aredenoted by the same reference numerals of the first embodiment and theexplanation thereof is omitted herein.

With the thus arranged second embodiment, the same advantages gained bythe first embodiment are also ensured. Further, it becomes possible todecrease the number of parts necessary for connecting the pinion gear 20with the driving device 23 a since the second embodiment is arranged tocoaxially connect the pinion gear 20 and the output shaft 24 of thedriving device 23 a. This reduction of the number of parts alsocontributes to decreasing the steps for the assembling operations of theair conditioning apparatus and the cost thereof. Furthermore, since thesecond embodiment is arranged such that the housing opening 25 forassembling the parts of the mix door assembly 10 a is covered with thecase of the driving device 23 a, a part necessary for closing thisopening 25 is omitted. This also contributes to decreasing the steps forthe assembling operations of the air conditioning apparatus and the costthereof. Further, sealing between the driving device 23 a and thehousing 80 a is ensured by the arrangement of the second embodiment.

Referring to FIG. 8, there is shown a third embodiment of the airconditioning apparatus according to the present invention.

The side wall of the case 60 has a case opening 40 through which the mixdoor assembly 10 b and the evaporator 3 are installed to the case 60.The air conditioning apparatus of the third embodiment is assembled in amanner that the case opening 40 is covered by a service cover 41 and isfixedly connected to the service cover 41 by means of screws after theevaporator 3 and the mix door assembly 10 b are assembled in the case60. A projection 41 a is formed at the peripheral surface of the servicecover 41, and a recess 40 a is formed at the peripheral surface of thecase opening 40. The projection 41 a of the service cover 41 issealingly connected to the recess 40 a around the case opening 40 by aspigot connection. Urethane foam may be employed instead of the spigotconnection for ensuring the sealing between the case 60 and the servicecover 41. Upper and lower openings 34 b for passing through air flow areformed in the housing 80 b as shown in FIG. 8. The other parts andconstruction of the third embodiment are the same as those of the firstembodiment shown in FIGS. 1 to 6. Therefore, the same elements aredenoted by the same reference numerals of the first embodiment and theexplanation thereof is omitted herein. The side wall of the housing 80has an opening 80e through which the pinion gear 20 and the shaft 22 areinserted through.

With the thus arranged third embodiment, the same advantages gained bythe first embodiment are also ensured. Further, when the evaporator 3 isinstalled to the case 60 from the case opening 40, the mix door assembly10 b is also assembled to the case 60 through the case opening 40.Therefore, the steps for the assembling operations of the airconditioning apparatus and the cost thereof are decreased thereby.

This installation method of the evaporator 3 and the mix door assembly10 improves the easiness of the maintenance of the mix door assembly 10.Further, easiness of assembling the air conditioning apparatus isimproved by the arrangement of the third embodiment, and therefore theair conditioning apparatus of the third embodiment ensures the easinessof the adaptation to recycle.

Referring to FIG. 9, there is shown the mix door assembly 10 c employedin the air conditioning apparatus according to a fourth embodiment ofthe present invention.

The fourth embodiment is arranged such that the evaporator 2 isinstalled in the housing 80 c of the mix door assembly 10 c. The housing80 c is constituted by a pair of housing members 51 and 52 which are incontact with each other at a center in the lateral direction as shown inFIG. 9. Each housing member 51, 52 has upper and lower openings 53. Acover plate 55 for covering the case opening 54 of the case 60 isintegrally formed with the housing member 51. Urethane foam is installedto an inner periphery of the cover plate 55 so that the cover plate 55is sealingly connected to the case 60. In stead of this seal member madeof urethane foam, the cover plate 55 and a peripheral portion of thecase opening 54 may be arranged to have a projection and a recess,respectively, so as to establish a sealing connection therebetween.

The evaporator 3 is provided with a connecting portion 56 includingrefrigerant inlet and outlet at a surface of the evaporator 3 facingwith the cover plate 55. The connecting portion 56 is connected througha cutout hole 58 formed at the cover plate 55 to an integral-typeexpansion valve unit 57 including an expansion valve and inlet andoutlet ports.

This arrangement of the evaporator 3 enables piping of a refrigerantconduit to be executed at an outside of the case 60. Therefore, the airconditioning apparatus of the fourth embodiment preferably ensures theadvantages in production process and in adaptability to variousvehicles. The other parts and construction of the fourth embodiment arethe same as those of the first embodiment shown in FIGS. 1 to 6.Therefore, the same elements are denoted by the same reference numeralsof the first embodiment and the explanation thereof is omitted herein.

In the assembly process of the air conditioning apparatus according tothe fourth embodiment of the present invention, the following steps (1)to (3) are executed.

(1) The mix door 70, the slide mechanism 90 including the pinions 20,and the evaporator 3 are installed to the housing 80 c to previouslyassemble the mix door assembly 10 with the evaporator 3. Theintegral-type expansion valve unit 57 is installed to the evaporatorthrough the housing 80 c.

(2) The heater core 4 and various mode doors 6 to 8 are installed to thecase 60 so as to produce the integral unit except for the mix doorassembly 10.

(3) The mix door assembly 10 is inserted to the case 60 through the caseopening 54. After the insertion of the air mix door assembly 10, thecover plate 55 is fittingly connected to the case opening 54 and isfixed to the case 60 by mean of screws or clips.

(4) A gear for transferring the rotational force generated by thedriving device 23 is engaged with a drive gear 22 integral with thepinion gear 20. It is of course that the driving device 23 may bepreviously installed to the cover plate 55 of the housing 55.

With the thus arranged fourth embodiment, the same advantages gained bythe above-mentioned embodiments are also ensured. Further, theevaporator 3 and the mix door 70 are simultaneously installed to thecase 60 from the case opening 45. Therefore, the steps for theassembling operations of the air conditioning apparatus and the costthereof are decreased. Further, it becomes possible to easily executethe maintenance of the evaporator 3. Furthermore, during suchmaintenance of the evaporator 3, the housing 80 c functions as aprotector of the evaporator 3 so as to prevent the evaporator 3 frombeing damaged.

Referring to FIGS. 10 and 11, there is shown a fifth embodiment of theair conditioning apparatus according to the present invention.

As shown in FIG. 10, first and second sensors S1 and S2 are installed toa back surface 3 a of the evaporator 3. The first sensor S1 is atemperature sensor for detecting a temperature of cool air passedthrough the evaporator 3. The first sensor S1 outputs a first signalindicative of the evaporator outlet air-temperature the control unit ofthe air conditioning apparatus in order to execute an automatic control.The second sensor S2 is a temperature sensor for detecting a temperatureof a radiation fin of the evaporator 3 and outputs a second signalindicative of the radiation fin temperature to the control unit in orderto properly control the operation of a compressor for refrigerationsystem of the air conditioning apparatus.

As shown in FIGS. 10 and 11, the housing 80 d of the mix door assembly10 d has both side wall 32 d and 32 d which respectively have cutoutportions 36. By the provision of these cutout portions 36, the mix doorassembly 10 d is easily installed to and detached from the case 6through the case opening without colliding with the first and secondsensors S1 and S2. These cutout portions 36 are formed at the both sidewalls 32 d and 32 d of the housing 80 d and so as to sandwich aninsertion holes 37 of the shaft 21. As is clearly shown in FIG. 11, thehousing 80 d has four openings 34 d for passing through air flow. Theother arrangement except for the above-mentioned explanation is the sameas that of the first embodiment shown in FIGS. 1 to 6. Therefore, thesame elements are denoted by same reference numeral as same as those ofthe first embodiment, and the explanation thereof is omitted herein.

With the thus arrange fifth embodiment according to the presentinvention, even if the sensors S1 and S2 are protrudingly installed tothe back surface of the evaporator 3, it is possible to installed themix door assembly 10 d through the case opening to the case 60 withoutcolliding with the sensors S1 and S2. Therefore, the mix door assembly10 d is located in the vicinity of the evaporator 3 even if the sensorsS1 and S2 are installed to the back surface 3 a of the evaporator 3.This enables the air conditioning apparatus to be made in small size.

Referring to FIGS. 12 to 18, there is shown a sixth embodiment of theair conditioning apparatus according to the present invention.

Main elements of the air conditioning apparatus according to the sixthembodiment of the present invention are assembled into an airconditioning unit 101.

A unit case 102 of the air conditioning unit 101 is of a two-piecestructure which is divided into right and left pieces along a parallelsurface of a paper of FIG. 14. The unit case 102 encases a blower fan103, a cooling heat exchanger (evaporator) 107, a mix door assembly 109and a heating heat exchanger (heater core) 108. Further, the unit case102 defines an air conditioning passage 106 through which air conveyedby the blower fan 103 is directed to upper openings 104 and 105. Theevaporator 107, the mix door assembly 109 and the heater core 108 arearranged in the air conditioning passage 106 in the order of mentionfrom the upstream side to the downstream side of the air conditioningpassage 106. Further, a swing-type door 110 is installed at a downstreamside of the evaporator 107 and the heater core 108, and a swing-typedoor 111 is installed at an end portion of the air conditioning passage106.

The blower fan 103 is installed in an arc-shaped housing 12 formed at anupper position in the unit case 102 and is rotated by a drive motor (notshown).

The housing 112 has a blower inlet port 113 through which air is drawnby the blower fan 103 and a blower outlet port 115 through which air isdirected toward the evaporator 117 through the air conditioning passage106.

The air conditioning passage 106 includes a downward passage (orupstream section) 106A, a U-turn lower passage (or intermediate section)106B and an upward passage (or downstream section) 106C which are allsections of the air conditioning passage 111, connected in series toform a single continuous path. The downward passage 106A extendsdownward continuously from the blower outlet port 115 on a first sideregion near a passenger compartment 114 of the vehicle. The U-turn lowerpassage 106B extends continuously from the downstream end of thedownward passage 106A located in the first side region near thepassenger compartment 114, to a second side region near an engine room(or engine compartment) 116 of the vehicle and turns the flow directionupward. The upward passage 106C extends upward continuously from thedownstream end of the U-turn lower passage 106B to the upper outlet(104, 105) of the unit case 102.

The unit case 102 has a first side wall (or first end or rear wall)102A, a second side wall (or second end or front wall) 102C, a lower (orbottom) wall 102B, an upper wall 102D, and left and right (or third andfourth) side walls 117. The first side (rear) wall 102A has an outsidesurface facing the passenger compartment 114, and inside surfacedefining the downward passage 106A with the left and right walls 117.The lower (bottom) wall 102B defines the lower U-turn passage 106B withthe left and right side walls 117. The second side (front) wall 102C hasan outside surface facing toward the engine compartment 116, and aninside surface defining the upward passage 106C with the left and rightwalls 117 and the outside surface of the surrounding wall of the blowerhousing 112.

The evaporator 107 and the heater core 108 are disposed in the lowerU-turn passage 106B. The evaporator 107 is located upstream of theheater core 108. The evaporator 107 on the upstream side has therein arefrigerant pipe for refrigerant, and numbers of fins. The evaporator107 is supported in the unit case 103 by upper and lower supportbrackets 118. The evaporator 107 is in an erecting or upright posture.In this example, the evaporator 107 leans slightly toward the heatercore 108. A leaning angle of the evaporator 107 is in the range from 0to about 30°. Preferably, the leaning angle is equal to 20°. The upperend of the evaporator 107 is located above the lower end and on theengine compartment's side of the lower end of the evaporator 107. Inthis arrangement, the air from the blower outlet port 115 of the blowerhousing 112 is introduced through the downward passage 102A into theevaporator 107. In the evaporator 107, the air can flow throughinterspaces among the fines in an effective manner following thespecification standards, and thereby achieve an effective heat transferfor cooling.

The evaporator 107 is a constituent member of a refrigeration cycle witha compressor, a condenser and an expansion valve. The refrigerantdischarged from the compressor flows through the condenser and theexpansion valve to the evaporator 107, and returns from the evaporator107 to the compressor.

The heater core 108 is, as shown in FIG. 12, installed at a lower sidelower than a line connecting the lower end portion of an air outlet ofthe evaporator 107 and a supporting shaft 110A of the door 110. Theheater core 108 is supported in the unit case 102 by front and rearsupport brackets 119 so as to be in a horizontally lying posture. Morespecifically, the heater core 108 is located at a position lower than aline connecting the door supporting shaft 110A and an upper end of themix door 110 under a full cool mode. It is preferable that the heatercore 108 slightly raises toward the evaporator 107 from the horizontallylying posture so as to form an angle 10° between the slightly raisingangle of the heater core 108 and a horizontal line. By this posture ofthe heater core 108, the heater core 108 is positioned with respect tothe evaporator 107 so as to form the shape of a letter T. Thislaid-low-T-shaped arrangement helps decrease the vertical dimension ofthe layout of the evaporator 107 and the heater core 108.

The heater core 108 is supplied with water heated by the engine of thevehicle, and arranged to perform the heat exchange for heating, with airpassing therethrough.

Next, the structure of the mix door assembly 109 will be discussed withreference to FIGS. 15 and 16. The mix door assembly 109 comprises aframe (housing) 120, a mix door 121 slidably installed to the frame 120,a drive shaft 122 and a driving device (not shown) for rotating thedrive shaft 122. The housing 120 comprises a pair of side plates 123which are formed into a shape defined by an arc and a straight lineconnecting both end of the arc. The side plates 123 are oppositely facedwith each other while having a predetermined distance and a parallelrelationship. Each side plate 123 has a shaft opening 123A and upper andlower guide grooves 123B. The shaft opening 123A is formed at a centerportion of the side plate 123. The upper and lower guide grooves 123Bare formed along the arc-shaped periphery and are separated at thecenter portion. Further, two insertion grooves 123C for installing guiderollers of the mix door 121 to the frame 120 are formed perpendicular tothe guide grooves 123B. A distance between the side plates 123 are setat a value generally the same as a width dimension of the air passageregion of the evaporator 107. Upper and lower frames 124 interconnectthe side plates 123. Further, a door guide plate 125 is installed to thearc-shaped periphery of each side plate 123 to guide the slide movementof the mix door 121. A center guide plate 126 of an arc-shape connectscenter portions of the upper and lower frames 124. Both center portionsof the side plates 123 and the center portion of the center guide plate126 are connected by a reinforcement plate 127. The reinforcement plate127 and the center guide plate 126 form a cross shape and define upperfirst and second openings 128A and 128A and lower first and secondopening 128B and 128B, as shown in FIG. 15.

The mix door 121 is a curved rectangular plate whose curved surfaceextends along the curve of the frame 120. The mix door 121 is installedto the frame 120 so as to be slidable on the guide plates 126 and 127 inthe direction h shown in FIG. 15. Four slide pins 129 are formed at fourcorners of the mix door 121 so as to extend in the direction w of FIG.15. Further, each slide pin 129 is covered with a guide roller 129A madeof high-lubricity material. A pair of racks 30 are formed on bothlateral end portions of an inner surface of the mix door 121 in thedirection h. The lateral dimension of the mix door 121 is generally thesame as the distance between the side plates 123. The vertical dimensionof the mix door 121 is set to be slightly greater than a half of thevertical dimension corresponding to a dimension in the direction h ofthe frame 120. Therefore, when the mix door 121 is installed to theframe 120, the mix door 121 is slidable so as to close or open eitherthe upper openings 128A or the lower openings 128B.

A drive shaft 122 has a longitudinal dimension which is generally thesame as that of the dimension in the direction w of the mix door 121. Apair of cylindrical members 132 are fixedly installed to both ends ofthe drive shaft 122. A pinion gear 131 is formed on an outer peripheryof each cylindrical member 132. Further, a small cylindrical shaft 132Aprojects from an outer surface of each cylindrical member 132 so as tobe coaxial with the cylindrical member 132. These small cylindricalshafts 132A are rotatably supported to the shaft openings 123A of theside plates 123, respectively. A connecting recess 132B is formed at anouter surface of the small cylindrical shaft 132A so that the smallcylindrical shaft 132A is connected to a rotation drive device (notshow) through the connecting recess 132B. FIG. 16 is a perspective viewshowing the mix door assembly 109.

The air mix door assembly 109 has a rigidity in the direction w by meansof the drive shaft 122 installed to the side plates 123. Upon takingaccount of the deformation (twist and distortion) of the unit case 102,the frame 120 is designed so as to deflect by receiving a predeterminedmagnitude of stress. Further, the guide grooves 123B for slidablyreceiving the guide rollers 129 are designed to have a predetermineddimensional margin in width thereof. Therefore, even if the unit case102 is slightly deformed, the mix door 121 smoothly slides on the frame120. The flexibility of the frame 120 can be properly set by properlyselecting material and thickness of the frame 120. A damper sheet 143made of urethane foam is attached on at least an outer surface of upperand lower frames 124 as shown in FIG. 17.

A pair of position pins 123D project from one of the side plate 123toward the case unit 102 as shown in FIGS. 16 and 17. The unit case 102has a pair of positioning recesses engaged with the position pins 123Dalthough they are not shown in Figures. By this provision of theposition pins 123D and the positioning recesses, the mix door assembly109 is easily and correctly installed to the unit case 102. Accordingly,this arrangement enables the air conditioning apparatus to be quicklyand correctly assembled while keeping the connection accuracy betweenthe mix door assembly 109 and the rotation drive device.

As shown in FIGS. 12 and 13, the mix door assembly 109 is supported todoor-supporting brackets 133 which are integrally formed with supportingbrackets 118 of the unit case 102. As mentioned above, since the dampersheet 143 is attached on the outer surface of the upper and lower frame124 and is sandwiched by the frame 120 and the brackets 133, a deformingforce generated at the unit case 102 is absorbed by the damper sheet 143so as to suppress the deformation stress of the unit case 102 from beingtransferred to the frame 120 of the mix door assembly 109. Both outersurfaces of the side plates 123 are fittingly in contact with both innersurface of the unit case 102 while the position pins 123D are engagedwith the positioning recesses of the unit case 102.

The mix door assembly 109 is installed to the unit case 102 so that theprotruding surface of the mix door assembly 109 faces the downstreamside of the air conditioning passage 106 and that the upper openings128A are located at an upper position and the lower openings 128 b arelocated at a lower position as is clearly shown in FIG. 12. Under acondition that the mix door assembly 109 is installed to the unit case102, the rotation drive device is connected to the connecting recess132B of the cylindrical member 132 so that the cylindrical member 132 isrotated according to the operation of the rotation drive device.

The upper openings 104 and 105 are formed at a front wall 102C of theunit case 102 in the vicinity of the engine compartment 116 and an upperwall 102D continuous to the front wall 102C, respectively. The upperopening 104 formed at the front wall 102C functions as a defroster port,and the opening 105 formed at the upper wall 102D functions as aventilation port (vent. port). As shown in FIG. 12, the door 111 isdisposed in the vicinity of the openings 104 and 105 and alternativelyopens the openings 104 and 105 according to a manual control of avehicle passenger or an automatic control of a control unit of the airconditioning apparatus.

As shown in FIG. 12, a ventilator duct 134 is connected to the upperopening 105. The ventilator duct 134 has several outlet ports throughwhich air-conditioned air is supplied from the air conditioningapparatus to the passenger compartment 114. A distance between the upperopening 105 and the outlet port 134C of the center portion is set at arelatively long distance as compared with those of the other right andleft outlet ports so that the air-conditioned air equivalently flows outfrom the center outlet port 134C and the right and left outlet ports. Adefroster duct 136 is connected to the upper opening 104 so that theconditioned air is blown through the ventilator duct 134 toward thefront window glass 135. A foot outlet port 137 for delivering theair-conditioned air to a lower portion of the passenger compartment 114is formed between the heater core 108 and the door 110. Theair-conditioned air is directed to the foot outlet port 137 when thedoor 110 is opened. A drain reservoir 138 is formed under the evaporator107 and receives liquidized water on the outer surface of the evaporator107. The drain receiver 138 is covered with a partition plate 139 so asnot to be directly affected by the air flowing through the evaporator107. A drain port (not shown) is formed at a bottom portion of the drainreservoir 138.

With the thus arranged air conditioning apparatus of the sixthembodiment, the air discharged from the blower fan 3 passes through theevaporator 108 and thereafter passes or bypasses the heater core 108.Then, the cooled and/or heated air is mixed in the air mix chamber 140and is conditioned therein. The conditioned air is delivered to thepassenger compartment 114 according to the open and close control of thedoors 110 and 111.

When the conditioned air is blown out through the ventilator duct 134 tothe passenger compartment 114, the conditioned air flows up along theupward passage 106C and along a back surface of the arc-shaped housing112 so as to smoothly convey the conditioned air to the ventilator duct134. Further, since it is possible to ensure a relatively long distanceto the center outlet port 134C, smooth air stream having a smallerflow-resistance is generated as shown by an arrow a of FIG. 12. Thisenables the conditioned air to be delivered equivalently through thecenter outlet port 134C, right and left outlet ports to the passengercompartment 114.

Further, since the open and close door 111 is disposed near the enginecompartment 116 and apart from the passenger compartment 114, noises dueto the opening and closing operation of the open and close door 111tends to be suppressed. Furthermore, it is possible to fixedly installthe air conditioner unit 101 to the automotive vehicle by utilizing asteering fixing member 141 shown in FIG. 12. In such an installationcase, a back side of the air conditioner unit 101 is supported to thesteering fixing member 141, and therefore the installation position ofthe door 111 is apart from the supporting position. Accordingly, thedistortion of the unit case 102 tends not to be transferred to the openand close door 111, and therefore the door 111 maintains its smoothoperation. Furthermore, since the mix door assembly 109 is installed tothe unit case 102 through the damper sheet 143, even if distortion isgenerated at the unit case 102, the distortion of the unit case 102 issuppressed by the damper sheet 143. This improves the reliability of theslide mechanism of the mix door assembly 109.

While the present invention has been described in the preferredembodiments, it is to be understood that the invention is not limitedthereto but may be otherwise variously embodied without departing fromthe sprit of the invention.

For example, the mix door may not be formed into arc-shape toward theair flowing direction, and it may be formed into a flat shape or into areverse arc-shape in some cases. Further, the slide mechanism may beproperly redesigned according to the modification of the pinion gear andthe rack. Furthermore, it will be understood that a plurality ofpartition plates may be arranged in parallel in the air mixing regionand that a plurality of mix doors may be independently disposed at anupstream side of the partitioned air mixing region. Even in this case,the steps for assembling the air conditioning apparatus are largelydecreased by employing the detachable mix door assembly.

Furthermore, the evaporator and the heater core may be arranged so thatthe heater core in a lying (horizontal) posture is located above theevaporator in a lying horizontal) posture, and the mix door assembly maybe installed between the evaporator and the heater core so that the mixdoor can slide in a generally horizontal direction.

Furthermore, it will be understood that the installation of the mix doorassembly is not limited to an insertion method through the openingformed at the side wall of the case and may be freely installed to thecase. For example, the mix door assembly may be installed to the casewhen the divided two case members are assembled into the case. Further,the mix door assembly may be sandwiched by the cooler unit and theheater unit which are independently assembled. Even when the mix doorassembly is made to be adaptable to various arrangements, it can ensurea performance in assembly operation and decrease the production cost.Further, the mix door assembly can ensure a high flexibility inadaptation to various air conditioning apparatuses. Additionally, sincethe mix door assembly can ensure a stability in slide movementindependently, the reliability of the operation of the air conditioningapparatus is improved.

Furthermore, it will be understood that application of the mix doorassembly is not limited only to the air mixing door, and may be adaptedto various doors, such as mode doors, and may be employed instead of aswing-type door.

The contents of Applications Nos. 2000-72415 with a filing date Mar. 15,2000 and H11-294510 with a filing date Oct. 15, 1999 in Japan are herebyincorporated by reference.

What is claimed is:
 1. An air conditioning apparatus for an automotivevehicle, said air conditioning apparatus comprising: a case having anopening formed at a side wall of said case, said opening configured topermit installation therethrough of a preassembled mix door assembly; aheater core installed in said case; and said mix door assembly adaptedto be detachably installed in said case through the opening, said mixdoor assembly adapted to vary a ratio of a quantity of air passingthrough said heater core to a quantity of air bypassing said heatercore, said mix door assembly comprising: a housing, a mix door installedin the housing, and a slide mechanism installed in the housing, theslide mechanism receiving a rotational force and sliding the mix doorwith respect to the housing according to the received rotational forceto vary the ratio wherein the slide mechanism of said slide doorassembly includes a pinion gear whose center is coaxially connected to arotational axis of a driving device, and a rack formed on the mix door,the pinion gear being engaged with the rack, and wherein an opening isformed in a side wall of the housing, the pinion gear and the shaftconnected with the pinion gear being inserted into the housing throughthe opening, and the opening being closed by a case of the drivingdevice.
 2. The air conditioning apparatus as claimed in claim 1, whereinthe driving device supplies the rotation force to the slide mechanism,the driving device being installed on a side wall of the housing.
 3. Theair conditioning apparatus as claimed in claim 1, further comprising anevaporator, installed in said case, for cooling air discharged into saidcase.
 4. An air conditioning apparatus as claimed in claim 3, whereinthe evaporator installed in the case has a connecting portion includingrefrigerant inlet and outlet ports, the connecting portion beingarranged to be connected to a refrigerant line at the outside of saidcase.
 5. The air conditioning apparatus as claimed in claim 1, furthercomprising an evaporator for cooling air flowing in said case.
 6. Theair conditioning apparatus as claimed in claim 5, wherein said casedefines an air conditioning passage which is divided into a warm airpassage and a cool air passage at a downstream side of the evaporatordisposed in the air conditioning passage, the warm air passage beingarranged so that air passing through the evaporator passes through saidheater core, the cool air passage being arranged so that air passingthrough the evaporator bypasses said heater core.
 7. An air conditioningapparatus for an automotive vehicle, said air conditioning apparatuscomprising: a case having an opening formed at a side wall of said case,said opening configured to permit installation therethrough of apreassembled mix door assembly; a heater core installed in said case;said mix door assembly adapted to be detachably installed in said casethrough the opening, said mix door assembly adapted to vary a ratio of aquantity of air passing through said heater core to a quantity of airbypassing said heater core, said mix door assembly comprising: ahousing, a mix door installed in the housing, and a slide mechanisminstalled in the housing, the slide mechanism receiving a rotationalforce and sliding the mix door with respect to the housing according tothe received rotational force to vary the ratio; and an evaporator forcooling air flowing in said case, wherein a temperature sensor isprotrudingly installed at a downstream surface of the evaporator throughwhich air flows, said mix door assembly being arranged so as not tocollide with the sensor when said mix door assembly is installed to anddetached from said case.
 8. The air conditioning apparatus as claimed inclaim 7, wherein the housing of said mix door assembly has a cutoutportion which avoids said mix door assembly from colliding with thesensor.
 9. The air conditioning apparatus as claimed in claim 7, whereinsaid case defines an air conditioning passage which is divided into awarm air passage and a cool air passage at a downstream side of theevaporator disposed in the air conditioning passage, the warm airpassage being arranged so that air passing through the evaporator passesthrough said heater core, the cool air passage being arranged so thatair passing through the evaporator bypasses said heater core.
 10. An airconditioning apparatus for an automotive vehicle, said air conditioningapparatus comprising: a case having an opening which is formed at a sidewall of said case and a service cover which detachably covers theopening, said opening configured to permit installation therethrough ofa preassembled mix door assembly; a heater core installed in said case;and said mix door assembly adapted to be detachably installed in saidcase through the opening, said mix door assembly adapted to vary a ratioof a quantity of air passing through said heater core to a quantity ofair bypassing said heater core, said mix door assembly comprising: ahousing having a partition wall which defines at least two openings; amix door installed in the housing; a seal member attached to aperipheral surface of the mix door, the seal member being fitted withthe housing when the mix door is positioned at one of an uppermostposition and a lowermost position relative to the housing; and a slidemechanism installed in the housing, the slide mechanism adapted toreceive a rotational force and to slide the mix door with respect to thehousing according to the received rotational force to vary the ratio.11. The air conditioning apparatus as claimed in claim 10, wherein theseal member is fitted with a partition wall of the housing when the mixdoor is positioned at one of an uppermost position and a lowermostposition relative to the housing.
 12. An air conditioning apparatus foran automotive vehicle, said air conditioning apparatus comprising; acase having an opening which is formed at a side wall of said case and aservice cover which detachably covers the opening, said openingconfigured to permit installation therethrough of a preassembled mixdoor assembly; a heater core installed in said case; and the mix doorassembly adapted to be detachably installed in said case through theopening, said mix door assembly adapted to vary a ratio of a quantity ofair passing through said heater core to a quantity of air bypassing saidheater core, said mix door assembly comprising: a housing having apartition wall which defines at least two openings, each opening beingcommunicated with one of a warm air passage and a cool air passage; amix door installed in the housing; a seal member attached to aperipheral surface of the mix door, the seal member being fitted withthe housing when the mix door is positioned at one of an uppermostposition and a lowermost position relative to the housing; and a slidemechanism installed in the housing, the slide mechanism adapted toreceive a rotational force and to slide the mix door with respect to thehousing according to the received rotational force to vary the ratio.